The present invention relates generally to operations performed in conjunction with subterranean wells and, in an embodiment described herein, more particularly provides methods and apparatus for drilling and completing a wellbore junction.
A continuing need exists for apparatus and methods which facilitate economical and time conserving completions of wells. Specifically, the drilling and completions of wells wherein intersecting wellbores are to be formed demand relatively complex apparatus and time-consuming procedures which, accordingly, tend to be relatively expensive. Thus, the need for improved apparatus and methods for drilling and completing intersecting wellbores is even greater than that for wells in general.
In particular, where intersecting wellbores are to be formed in a well, it is desirable to minimize the number of trips into the well and the amount of time spent performing operations during each trip. Therefore, it would be desirable to provide apparatus and methods which permit operations to be combined within a single trip, and which reduce the amount of time spent performing each operation.
In this regard, it is sometimes appropriate to retrieve a whipstock from a well after drilling a branch wellbore by using a milling tool to mill away a portion of the whipstock. Such milling operations tend to be very time-consuming. Thus, it would be advantageous to provide apparatus and methods which reduce the amount of time spent milling whipstocks.
Additionally, a problem arises when intersecting wellbores are formed as to how to seal the intersection between the wellbores. One facet of this problem relates to how to isolate a formation adjacent or surrounding the wellbore intersection from the wellbores themselves. Another facet of this problem relates to how to isolate fluids produced from, or injected into, formations intersected by each wellbore from those produced from, or injected into, other wellbores, and other portions of the same wellbore. Therefore, it would be advantageous to provide apparatus and methods which facilitate economical and convenient wellbore intersection sealing.
In carrying out the principles of the present invention, in accordance with an embodiment thereof, apparatus and methods are provided which permit the forming and completion of wellbore intersections in a convenient, efficient and economical manner.
In one aspect of the present invention, apparatus for use in completing a subterranean well is provided. The apparatus includes a cutting tool diverter assembly in which a diverter thereof has a relatively easily millable outer portion. For retrieval of the diverter, a method is provided in which the diverter outer portion is milled, for example, by a washover shoe.
The apparatus may include a packer engagement assembly which serves to provide engagement between the diverter assembly and a packer of the apparatus. The packer engagement assembly may include a latching device for releasably securing the diverter assembly relative to the packer. The packer engagement assembly may include an orienting device for orienting the diverter assembly relative to the packer. The packer engagement assembly may also permit fluid communication between an inner fluid passage of the diverter assembly and a pressure setting port of the packer.
In another aspect of the present invention, a method is provided in which a wellbore intersection is sealed by injecting a substance into a formation surrounding or adjacent the wellbore intersection. The injection operation may be performed after a first portion of a branch wellbore is drilled, but before a second portion is drilled. After the second portion is drilled, a tubular member is positioned in the branch wellbore so that one end of the tubular member is within the first portion and the other end is within the second portion. The tubular member is sealingly engaged in the branch wellbore first portion, thereby isolating the formation surrounding the wellbore intersection from the intersecting wellbores.
These and other features, advantages, benefits and objects of the present invention will become apparent to one of ordinary skill in the art upon careful consideration of the detailed descriptions of representative embodiments of the invention hereinbelow and the accompanying drawings.